Uh Oh. It looks like someone isn’t keeping up with the Marginal Gains podcast.

To be clear, I am not *arguing* with you. You do you, I have no issues with that. Think of this as more of a discussion than anything even remotely adverserial.

That said, re your 2 points, here are my thoughts:
1/ Sure, most people dont race. But they still like to go as fast as possible. That's why they buy carbon wheels, aero frames, etc. This is just more of the same, although with fewer tradeoffs (it isnt as if you are spending a lot more money to get some extra speed - GP5ks cost about the same as pretty much any other nice tire)
2/ I do agree that the watt savings in a lab may not translate to the same number in the real world - but it doesnt have to be lower. It could even be higher, for all we know. Regardless, in the absence of any numbers, doesnt it make sense to go with the tire that has greater odds of being faster, all else being equal?

The "all else being equal" is, admittedly, key. Handling and ride quality are great reasons to ride something else - on that front, not only do I agree with you here but also in practice: i ride Turbo Cottons and Veloflex myself, as well. There are logical reasons for not getting the GP5ks.

There is a difference between the following 2 statements:
- The extra watt savings of the GP5k are irrelevant
- The extra watt savings of the GP5k are not worth giving up on the ride feel/cornering abilities of the Veloflex Corsas

The former is illogical and cannot really be defended via arguments, other than "well, i dont care" (and I dont mean it in a judgemental way - hobbies dont have to be fully rational. I collect watches, FFS - talk about a rabbit hole devoid of reason). The latter makes a lot of sense.

ah gotcha my man!! And if you notice, I haven't argued that there isn't a rolling resistance advantage of the Conti either, but I'm arguing that people are putting WAY too much emphasis on ONE criteria of "going fast in the real world". Going fast involve a gazillion variables, and rolling resistance isn't a top one unless your cycling discipline is a very specific one matching that of the lab environment. Laboratory "watt saving" is always going to be higher than what is realized in real world. Always. You don't really need to ponder about this.

ugh oh..

This is what I said:

Notice that I was making a reference to myself, you know what they say, control the variables in testing right?
I wasn't bragging about my skills versus others.
But you didn't waste any opportunity to make an assesstment on my skills, did you?
But what the hell do I know about bike handling? I mean I've only dragged my knees at 80-100 mph around the local race track probably at least 100 sessions in the past decade or so, and still live to tell about it today. What do I really know compare to a superior cat1 cyclist like yourself! Pipe down, pal

Your skills, you knowledge: all lacking.

What do you know? Clearly very little, as is evidenced by each successive post you make. But you keep doubling down on your ignorance concerning the topic, and I'll keep laughing at it.

This "ONE criteria" has one of the most significant effects on speed that you can make from an equipment perspective; more important than wheels, frame, etc. For some inexplicable reason this escapes you. It is one of "a gazillion variables" most pertinent for emphasis when it comes to stuff that goes on your bike.

Perhaps you actually do need to ponder more about this. Don't strain yourself, though. I'm sure you're not well used to it.

https://marginalgainspodcast.cc/tire...er-tom-anhalt/

Here's a plot that translates the difference between a Conti GP4K (already a pretty good tire) and a Conti GP5K in terms of equivalent weight at different gradients. If you're a weight weenie, you should definitely be a Crr weenie.

so you keep laughing at my lack of skills/knowledge will make you better? Dude, you sound a little hurt inside or what?
Wake me up when tires make a differnce in someone winning or losing in a race. Only weekend warriors seem to focus on tires to this extent. Reminds of guys on the track getting passed on the brakes and then they blame it on having subpar brakes and tires. You understand that winning is first and foremost a state of mind. At some point you'll need to stop looking for marginal gains and start training a winning mind! Trust me pal I've competed at much higher level of 2 wheel sport than you could realize at your local cat1 bro's brawl.

Brag about your motorcycle a few more times; I think it’s working.

Again with the confirmation. You've lost the plot, bud.

cf. posts 51, 57. Just because you're not aware of it doesn't mean it isn't happening.

Guys, here is the truth;
None of us no what level of rider each other are because we have never been on a bike together.

overall IME the difference between ok tires and really good tires is huge. I remember when I went from michelin lithion2 to the lithio4...night and day. I ran vittoria corsa G+ for while and it is a great ride and handling tire, but I had huge flat issues. I am now running the conti 5000 no flats and almost no difference from the vittoria (am also doing a direct compare between the 5000 clinchers and vittoria corsa control tubular)

yes get conti 5000

The example I always use is the 1996 Elite Men's NCNCA (that is, Northern California Nevada) District Championship 40km TT. NCNCA is pretty competitive.

PLACE TIME NAME
-- ------- -------------------
1 52:56.3 DAVID LELAND
2 52:57.1 ANTHONY CRUZ
3 52:57.8 DAVID BAILEY
4 52:58.1 TIM GRANSHAW
5 53:00.9 GRAHAM SIMPSON

Not only did Granshaw lose a podium spot by 0.3 seconds overall over 40km -- if he'd been .05 sec/km faster he'd've won the whole damn thing. That's 1/20th of a second per km, and 1/20th of a second is literally the blink of an eye. That was the difference between winning and not standing anywhere on the podium and a long quiet drive home.

ok, an almost 1 hour TT would be something I'll concede to the advantage of rolling resistance coming into play of final placement determination. But I'd also argue that an hour TT is a pretty specific discipline.
But how many guys in here who are emphasiszing the advantage of rolling resistance do one hour TTs and thinking at the level of "1/20th of a second per km" when they're hammering with their possies or a crit around an industrial park?

And what about descending, taking fast corners, and tire feedback? The GP4000 was bunk at this as a front tire because it's got hard rubber and hard casing. I'll take Vit Corsa and Veloflex with latex for the front, easily no question asked, because those gives supreme road feedback while trail braking into a corner. This is important too if you're that type of rider!

And don'y forget, this was for Northern CA. That's a pretty limited geographical area (even accounting for those who might have come from out of district). What about riders in the other 48 1/2 states? These results say nothing about them.

your reply should be directed at mr cat1. I wasn't the one to initially brag about skills.

If he had ridden his bike more instead of spending countless hours researching marginal gains maybe he would have been 0.05 sec/km faster?

My wife missed a slot for the 70.3 championships in Nice, France by 4s across a ~5 hour race. Slightly better tires would have gotten it. It's not just cycling TTs.

You usually research marginal gains during times when you couldn't be riding.

Relax folks, let us step back and review the OP's requirement and/or desire:

This is what he asked:

Googling shows that the cheapest Conti Ultrasport is $15, and the cheapest GP5000 is $35, that's more than double the price of an Ultrasport.

But OP's questioning also brings in a sense of "value judgement" as he's asking is the difference "big enough". What is "big enough". He doesn't tell us what is big enough he's looking for, maybe because he doesn't quite completely realize all the nuances to the question he's asking.
And from the tone of his questioning, he doesn't seem he's asking because he wants to go racing, and probably he's not asking this for his time trialing effort either, does it?

On the other hand, he stated that he has put thousand of miles on the Ultrasport and they've performed reliably. So I take it that reliability is an important factor. But OP also wants to know if the GP5000 will make him really notice the difference.

Well money may not be an object (and to what extent) to the OP, but I will assume that if he's asking this question, then money and the concept of value is an object to him. Will he appreciate going 1 second faster per kilometer if he switches to GP5000s? That's 100 seconds worth of saving in a 100km ride, now some of you say, there are 2 tires, so it shold be 200 seconds saving right? Not how it works. My position on this is clear, it don't make one bit of difference, save your money. Two tires is a saving of $40, is it not? And a cut GP5000 will cost more than twice to replace. Is this a big enough difference?

I, personaly, feel like some of you just emphasis one thing, rolling resistance, without addressing the OP's overall value question much. Now if OP was asking to hellbent shaving 100 seconds off his metric century, then ok, bring in the esoteric science!

I can make the same arguments for aero helmets, aero frames, wheels, pedals, shoes, jerseys, bibs, water bottles, and even helmlet straps (yes!), etc.. At the end of the day, there can only be a few top place qualifiers and a whole lot of disappointing non-qual's, and a load of in-race variables to ponder that can put you in analysis paralysis. If she doesn't do this for a living and doing it as a personal challenge thing, she should pad herself on the back and come back next year.

...yes, you should make that same argument. You make all the right choices, including low-RR tires. It doesn't put you in analysis paralysis, it just means you optimize the system and hope to at least not lose anything to your competitors based on that. I don't know why you think that picking the right tire is hard; the work was literally already done so all you have to do is order the correct one.

Can't brag about something you don't have!